Field of the Invention
The present invention relates to a concealed hinge for a window with a fixed frame and a turnable leaf.
In particular the invention relates to a concealed hinge for a turn-tilt and a tilt-turn window that can turn open around a vertical axis and tilt open around a horizontal axis depending on the position of the operating handle of the window.
Description of the Related Art
The leaf of the window is traditionally provided on its outer periphery with a fitting groove in which fitting slats are movably affixed, whereby these fitting slats can be moved in the one or the other direction by means of the aforementioned operating handle.
As is known, the window is provided with a number of locking points in the form of locking pins that are fastened to the fitting slats and which can engage with locking pieces on the inside of the fixed frame in order to lock the leaf in the closed position of the operating handle by hooking the locking pins in or behind the locking pieces, or to unlock the leaf by withdrawing the locking pins out of or behind the locking pieces by turning the operating handle in a suitable direction of rotation from the closed position.
When turning the operating handle in the aforementioned direction of rotation, either the window can first be brought to the turn position and with further turning of the operating handle it can then be brought to the tilt position, or first brought to the tilt position and only then to the turn position. In the first case it is called a turn-tilt window and in the second case a tilt-turn window. The present invention applies to both types of window. In the following, a turn-tilt window also means a tilt-turn window.
A concealed hinge is known in BE 1.017.348 that is mounted on the top of the window between the top horizontal profile of the fixed frame and the top of the leaf, and which is provided with a scissor mechanism with a main arm that is connected by a first end to the leaf by means of a hinge that is affixed on a carriage that is movably affixed in a guide, whereby this guide is intended to be fastened to the leaf across the fitting groove on the top of the leaf, so that a fitting slat can move thereunder that is provided with a locking piece that can engage with a locking pin on the main arm to be able to block or unblock the scissor mechanism with respect to the leaf by using the operating handle.
In the blocked situation of the scissor mechanism the leaf can turn open, while in the unblocked situation the leaf can tilt open.
It is also known in BE 1.017.348 that the main arm of the concealed hinge is coupled by its other second end to a scissor hinge with two scissor arms that are hingeable with respect to one another, whereby the scissor arms are hingeably connected by one end to the main arm, and are hingeably connected by their other end to a mounting slat with which the scissor mechanism can be fastened to the inside of the top horizontal profile of the fixed frame.
In the closed position of the window, the concealed hinge is folded up and the scissor arms of the scissor hinge, together with the mounting slat and the free end of the main arm of the scissor mechanism, are folded up above one another in the limited space between the fitting grooves of the leaf and the fixed frame in the corner of the window on the hinge side of the window.
The main arm is thereby logically mounted under the scissor arms by its second end, in other words by the end closest to the top of the leaf and thus the furthest from the mounting slat.
In order to provide as much space as possible under the main arm for the guide with carriage on the leaf, the main arm is provided with a double kink that divides the main arm into two sections that are located at a different height with respect to the mounting slat, respectively a higher first section that extends above the aforementioned guide and is connected thereto, and a lower second section with which the main arm is connected to the scissor hinge.
The double kink is such that the thickness of the two scissor arms is bridged, such that, in the mounted and folded-up situation of the concealed hinge, the higher first section of the main arm is approximately at the same height as the second scissor arm, that is situated the closest to the mounting slat.
As a result of this kink, in combination with the relatively large load of the main arm due to the relatively large weight of the glass, there is the risk that during tilting open and closing the main arm experiences relatively large bending, which can only be resolved by strengthening the main arm, however where there is little space for this in view of the limited clear space between the leaf and the fixed frame.
As a result of this limited space it is also difficult to provide an extra locking point at the location of the scissor hinge, except with a relatively complex and expensive solution. That is why an extra locking point is often not provided at this location, which is to the detriment of the seal of the window against wind and water.